1.She asked the Homeland Security Department for a security period that would end on January 24th.
security 安全
She hasn't been cleared by security.
她尚未獲保安部門批準做機要工作
。2.She asked the Homeland Security Department for a security period that would end on January 24th.
period 期間
The patients were observed over a period of several months.
這些病人被觀察了數月之久
。